Engineering and detection of light scattering directionalities in dewetted nanoresonators through dark-field scanning microscopy
Nicoletta Granchi, Luca Fagiani, Marco Salvalaglio, Chiara Barri, Andrea Ristori, Michele Montanari, Massimo Gurioli, Marco Abbarchi, Axel Voigt, M. A. Vincenti, Francesca Intonti, Monica Bollani
Abstract
Dewetted, SiGe nanoparticles have been successfully exploited for light management in the visible and near-infrared, although their scattering properties have been so far only qualitatively studied. Here, we demonstrate that the Mie resonances sustained by a SiGe-based nanoantenna under tilted illumination, can generate radiation patterns in different directions. We introduce a novel dark-field microscopy setup that exploits the movement of the nanoantenna under the objective lens to spectrally isolate Mie resonances contribution to the total scattering cross-section during the same measurement. The knowledge of islands' aspect ratio is then benchmarked by 3D, anisotropic phase-field simulations and contributes to a correct interpretation of the experimental data.